Arrays of small lenses having a diameter on the order of one millimeter are referred to as micro-lenses or lenslets. Structures incorporating the same have been made in a number of ways and are used for a variety of purposes. An array of micro-lenses has been matched to an array of pixels on a television screen or other raster imaging device. Another use, such as that illustrated in "Agile Beam Steering Using Binary Optics Microlens Arrays", by W. Goltsos and M. Holz, Optical Engineering Vol 29 No. 11, page 1392, is for steering a collimated beam of monochromatic radiation through an angle by translating one of a pair of binary micro-lens arrays that combine to form an array of Galilean telescopes. The beam is required to be monochromatic because binary micro-lenses are highly dispersive.
A variety of optical systems can be formed from select configurations of micro-optic multiplets (MOM) comprised of two or more micro-lens modules (MLM). The MLM's themselves are typically formed from planar arrays of micro-lenses. With these optical systems, a single primary image is formed together with a set of images transversely displaced from an optic axis. MOM's are characterized by the property that the image distance and the object distance move in the same direction, in stark contrast to known lens systems. For example, when an object distance decreases, the corresponding image distance also decreases with the present MLM optical system.
In some applications such as machine vision, the illumination pattern provided by conventional optical sources may not be a good match for a specific application. For example, a wider field illumination may be desirable than can otherwise be generated with conventional optical systems receiving light from optical sources. Moreover, since arrays of light emitting diodes (LED) and laser diode emitters are now available, control over the illumination field is needed. It would be advantageous to utilize pairs of micro-lens arrays to provide illumination control over multiple optical sources in an inexpensive manner. The present optical system is drawn towards such an invention.